In fabricating a semiconductor device or a LCD substrate, a resist pattern is formed on a substrate with the use of photolithography technique. In order to form a resist pattern on a semiconductor wafer (hereinafter referred simply to “wafer”), the wafer is coated with a resist liquid to form a resist film on the wafer, the resist film is exposed with the use of photomask, and then the resist film is subjected to a developing process. In general, the resist pattern formation is carried out by a resist pattern forming system composed of a coating and developing apparatus that coats and develops a resist and an exposure apparatus connected to the coating and developing apparatus.
JP2004-193597A discloses a coating and developing apparatus, which is schematically shown in FIG. 11. A carrier 10 holding therein plural wafers W is carried into a carrier stage 11 in a carrier block 1A, and the wafer W in the carrier 10 is transferred to a process block 1B by a transfer arm 12. The wafer W is conveyed to a coating unit 13A in the process block 1B where the wafer W is coated with a resist liquid, and then the wafer W is conveyed to an exposure apparatus 1D through an interface block 1C.
The exposed wafer is returned to the process block 1B where the wafer is subjected to a developing process in a developing unit 13B, and then the wafer is returned to the original carrier 10. Reference sign 14 (14a to 14c) denotes unit stacks, each provided with a heating unit and a cooling unit for heating and/or cooling a wafer W before and after the process performed by a coating unit 13A and/or developing unit 13B, and a transfer stage. In the process block 1B, the wafer W is transferred among the coating unit 13A, the developing unit 13B and the unit stacks 14a to 14c by transfer means 15A and 15B disposed in the process block 1B. In this case, all the wafers are transferred according to a transferring schedule specifying the timing at which each wafer is carried into respective units.
In the coating and developing apparatus of JP2004-193597A, since a common transfer means transfers a wafer to units for processing a wafer before exposure (e.g., a unit for resist film formation) and also transfers a wafer to units for processing a wafer after exposure (e.g., a developing unit), it is difficult to arrange an effective transferring schedule and thus to improve the throughput. This is contrary to the demands of improving the throughput of the coating and developing apparatus consistent with the improvement of the throughput of the exposing apparatus.
JP2001-176792A (JP3337677B2) discloses a coating and developing apparatus provided with an area for coating process and an area for developing process, wherein the areas are vertically separated from each other, and are provided therein with individual transfer means.
A certain kind of resist film requires antireflective film(s) formed over and/or under the resist film. In this case, if a unit block (i.e., a block composed of plural processing units) for forming a resist film, a unit block for forming an antireflective film before forming the resist film, a unit block for forming an antireflective film after forming the resist film and a unit block for developing process are stacked vertically, the total height of the coating and developing apparatus increases. Thus, it is difficult to transport the coating and developing apparatus from the manufacturing maker of the apparatus to the user. Moreover, the maintenance of the apparatus is difficult.
On the contrary, if liquid processing units such as a resist film coating unit and an antireflective film forming units are arranged in a plane, the footprint of the apparatus drastically increases.